Is it possible to unlock 3GS on 4.3.5?

[a27]

firmware 4.3.5.
modem 05.16.02.

I read that updating it to iPad Baseband (06.15) allows it to be unlocked.
Would that disable the GPS or anything please?

Thank you.

 

[labman]

iPad baseband is the only option. Tutorials and warnings are at Iclarified among others. Read before doing.